A method for a printing apparatus such as a printer is widely known in which a toner image formed on a photoreceptor drum is transferred to a recording medium for printout directly or via an intermediate transfer medium. In the printing apparatus employing such the method, toner is sometimes left on a surface of an image carrier which carries the toner image such as the photoreceptor drum or a transfer belt which functions as the intermediate transfer medium even after the toner image is transferred to the recording medium. For this reason, some printing apparatuses are provided with a cleaning mechanism which removes residual toner by a cleaning blade contacting on the surface of the photoreceptor drum or the transfer belt.
In such the cleaning mechanism, when toner at the edge of the cleaning blade is reduced due to a friction force generated between the edge and the contacting surface in a print process, in some cases, the edge is turned up and broken, an abnormal noise such as a chattering noise is generated, or toner passes through. Therefore, toner as a lubricant needs to be provided to the edge of the cleaning blade, and the cleaning blade needs to be protected.
For example, Unexamined Japanese Patent Application Kokai Publication No. 2011-090134 discloses a technique in which toner as the lubricant is sufficiently provided to the edge of the cleaning blade to prevent turn-up or deterioration of the edge, or generation of the abnormal noise, whereby the cleaning blade can attain a stable cleaning performance.
However, the amount of the lubricant needed for lubrication of the surface of the image carrier such as the photoreceptor drum or the intermediate transfer belt varies depending on a printing status. For example, since after performing printing at a high coverage rate, the amount of toner used is large, and the amount of toner left on the image carrier such as the photoreceptor drum or the intermediate transfer belt is also large, the amount of the lubricant needed is smaller than that after performing printing at a low coverage rate. For this reason, there are some cases in which when the same amount of lubricant is used regardless of the printing status, the amount of the lubricant consumed becomes large, thereby increasing running cost of the printing apparatus.